Project Summary (Pilot-Feasibility Core) This renewal application aims to continue research on rare eosinophilic gastrointestinal diseases with a focus on eosinophilic esophagitis (EoE), eosinophilic gastritis (EG), eosinophilic gastroenteritis (EGE), and eosinophilic colitis (EC) through the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR). CEGIR aims to advance the diagnosis, management, and treatment of these rare diseases. CEGIR will promote highly collaborative, multi-site, patient-centric, translational and clinical research with the intent of addressing unmet clinical trial readiness needs. The Pilot-Feasibility Core will support new ideas that have potential to create and/or change paradigms concerning EoE, EG, EGE, and EC. We plan to support at least two Pilot-Feasibility Clinical Research Projects during the course of this funding award. The Pilot-Feasibility Clinical Research Projects will last up to two years and ideally take maximum advantage of additional resources and/or data emerging through CEGIR. The projects will be collaborative among investigators within one or more CEGIR sites or with investigators outside the CEGIR environment. We aim to develop a selection process that 1) enables the testing of the most exciting and potentially novel hypotheses to develop proof-of-principle data that supports or refutes the new idea; 2) takes optimum advantage of the CEGIR and at the same time provides an opportunity for the participation of outside groups; 3) optimizes the chances of success of the identified projects; and 4) reports on the progress and discoveries made. We have already identified a series of exciting, cutting-edge ideas that could become Pilot-Feasibility Clinical Research Projects, and a process for optimally identifying, selecting, and carrying out these projects is described. In summary, this Pilot-Feasibility Core will financially, administratively, and scientifically support competitively selected projects that will provide foundational data for novel, paradigm-shifting clinical interventions and clinical trial readiness unmet needs for the rare eosinophilic diseases EoE, EG, EGE, and EC.